The present invention relates to a device for the vacuum-tight connecting of two bodies, especially a quartz body and a metallic body, each of which has an essentially tubular end section, and in the connected state of which, the tubular end section of the first body surrounds at least partially the end section of the second body. In another aspect, the present invention concerns an epitaxial system in which the connecting device can be used.
The present invention is used, for example, in epitaxial systems in which a quartz tube or the quartz container for receiving a material to be coated, e.g. wafers to be coated, is arranged. The material to be vapor-deposited is introduced by means of a quartz boat on one side of the quartz tube into the latter via a lock which can be closed vacuum-tight. The quartz tube is connected on the other side, for example, via a metallic housing to a vacuum pump apparatus in a vacuum-tight manner. Since temperatures between 500 and 800xc2x0 C. can be present in the quartz tube and, furthermore, since the latter can be under a very low vacuum (e.g. 10xe2x88x9210 hPa) high requirements in the area of vacuum technology must be put on such quartz-metal connections which result in complicated and expensive connections. Such different materials typically have large differences in coeficients of thermal expansion.
The handbook entitled xe2x80x9cTheorie und Praxis der Vacuumtechnikxe2x80x9d by Wutz, Adam, Walcher, Vieweg und Sohn Braunschweig, 1982 edition, pp. 478-479 discloses a connection of a glass tube to a metallic tube. The glass tube is inserted on one end into the metallic tube and connected to the metallic tube by a screw surrounding the glass tube. Two O-rings serve for the seal. However, this connection is suitable only for connecting vacuum measuring tube of glass to metallic apparatuses. At temperatures of 500xc2x0 C. to 800xc2x0 C. and a very low vacuum in the glass tube this connection no longer has a reliable seal. In addition, no measures have been taken to prevent the glass tube from being able to make contact with the metallic tube upon strong heating.
A flange connection between two tubes is disclosed on page 478 of the same handbook which connection makes use of a double seal with an intermediate conduit which can be evacuated. Between the flanges two annular chambers run, into each of which an O-ring is placed. The evacuatable intermediate conduit runs between the O-rings.
An object of the present invention is to be able to connect two bodies of different materials using a few components, for easy assembly and disassembly and to obtain a high sealing ability even at large temperature differences and very low pressures.